A detailed investigation on the degradation of WTe2 using Raman spectroscopy and surface analysis methods, including X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) was investigated. Single-, bi-, and tri-layer (1L, 2L, and 3L) WTe2 flakes are deposited on 290nm SiO2 on the top of Si. Once the samples are prepared, we promptly transfer them into a vacuum chamber and first measure Raman signals in vacuum at room temperature. Subsequently, we locate samples out of the vacuum chamber and measure them in ambient air conditions, starting from 5 minutes up to 15 days. During the measurement intervals, samples are stored in ambient conditions. We find relatively easy and fast degradation in single-layer WTe2 (less than 13 minutes for complete oxidation), which is much faster compared with that of many other 2D materials. The main driving force for degradation is oxidation of WTe2 into WOx and TeO2 on its surface, which appears to be a self-limiting process. Such unique degradation and oxidation behavior in WTe2 may result from low energy barrier for oxidation.
All Science Journal Classification (ASJC) codes
- Materials Science(all)